Product Description

The 1133 measures sound pressure level from 50dB to 100dB. This sensor is tuned to measure in the frequency range 100Hz to 8kHz. Outside this range the sensor's bandpass filter will drastically reduce the impact on the measured quantity.

First Look

After plugging in the 1133 into the HUB0000, and the HUB0000 into your computer, open the Phidget Control Panel. You will see something like this:

The Phidget Control Panel will list all connected Phidgets and associated objects, as well as the following information:

Serial number: allows you to differentiate between similar Phidgets.

Channel: allows you to differentiate between similar objects on a Phidget.

Version number: corresponds to the firmware version your Phidget is running. If your Phidget is listed in red, your firmware is out of date. Update the firmware by double-clicking the entry.

The Phidget Control Panel can also be used to test your device. Double-clicking on an object will open an example.

Voltage Input

Double-click on a Voltage Input object in order to run the example:

General information about the selected object will be displayed at the top of the window. You can also experiment with the following functionality:

Modify the change trigger and/or data interval value by dragging the sliders. For more information on these settings, see the data interval/change trigger page.

Select the 1133 from the Sensor Type drop-down menu. The example will now convert the voltage into sound pressure level (dB) automatically. Converting the voltage to sound pressure level (dB) is not specific to this example, it is handled by the Phidget libraries, with functions you have access to when you begin developing!

Technical Details

General

Sound pressure level (SPL) is measured in dB. The 1133 measures sound across a very wide range, with a frequency range of 100Hz to 8kHz and pressure level from 50dB to 100dB. The formula reports SPL , but the sensor is not sophisticated enough to be used as a substitute for a professional SPL Meter.

Formulas

The Phidget libraries can automatically convert sensor voltage into sound pressure level (dB) by selecting the appropriate SensorType. See the Phidget22 API for more details. The Formula to translate voltage from the sensor into a sound pressure level is:

Formula Dependencies

It is important to note that measuring SPL is very complex and depends on factors other than only the perceived volume. One of the major contributing factors is the frequency of the sound source. Different frequencies of a sine wave with identical amplitudes will generate very different sound pressure levels. Other factors can be the distance between the sound source and the microphone, and even the type of sound source, such as speakers. The bandpass filter of any speaker can affect the output gain at certain frequencies without any change in the volume knob of the speaker. Electrical noise in the power supplied to the sensor can affect the output. If the power supply is very noisy, this will introduce an offset in the output. It is much more noticeable when trying to measure smaller sound pressure levels due to the very small voltages of the microphone being affected much more. As a result, the previous formula is only accurate for a 1kHz pure tone. At other frequencies, there can be up to an 8dB difference between the calculated SPL and the output of a calibrated Sound Pressure Level meter.

Sensor Response

The following graph is the response of the 1133 to a 1kHz beep. The beep lasts 75ms. The 1133 has a response time of 1.40ms when placed 30 cm (11.9 inches) from the sound source. The output from the 1133 reduces to normal over the next 80ms.

The voltage output of the sensor can vary by up to 0.1V in a pressure-stable environment. This is especially noticeable at lower output voltages. The best way to deal with this is to average a handful of reported values.

Phidget Cable

The Phidget Cable is a 3-pin, 0.100 inch pitch locking connector. Pictured here is a plug with the connections labelled. The connectors are commonly available - refer to the Analog Input Primer for manufacturer part numbers.

What to do Next

General Phidget Programming - Read this general guide to the various aspects of programming with Phidgets. Learn how to log data into a spreadsheet, use Phidgets over the network, and much more.

Phidget22 API - The API is a universal library of all functions and definitions for programming with Phidgets. Just select your language and device and it'll give you a complete list of all properties, methods, events, and enumerations that are at your disposal.

Interface Boards and Hubs

This sensor can be read by any Phidget with an Analog Input or VINT Hub port. It will connect to either one using the included Phidget cable. VINT Hub ports can behave just like Analog Inputs, but have the added flexibility of being able to be used as digital inputs, digital outputs, or ports to communicate with VINT devices. For more information about VINT, see the VINT Primer.

Phidget Cables

This sensor comes with its own Phidget cable to connect it to an InterfaceKit or Hub, but if you need extras we have a full list down below. You can solder multiple cables together in order to make even longer Phidget cables, but you should be aware of the effects of having long wires in your system.

Have a look at our sound sensors:

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Phidgets Inc.

We believe in getting problems solved quickly and projects finished on time. That's why we specialize in making affordable, easy to use sensors and controllers that require minimal electronics knowledge.

Phidgets Inc.

We believe in getting problems solved quickly and projects finished on time. That's why we specialize in making affordable, easy to use sensors and controllers that require minimal electronics knowledge.